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Subject[tip: perf/core] perf/x86: Change x86_pmu::limit_period signature
The following commit has been merged into the perf/core branch of tip:

Commit-ID: 28f0f3c44b5c35be657a4f922dcdfb48285f4373
Gitweb: https://git.kernel.org/tip/28f0f3c44b5c35be657a4f922dcdfb48285f4373
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Tue, 10 May 2022 21:28:25 +02:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Wed, 07 Sep 2022 21:54:02 +02:00

perf/x86: Change x86_pmu::limit_period signature

In preparation for making it a static_call, change the signature.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220829101321.573713839@infradead.org
---
arch/x86/events/amd/core.c | 8 +++-----
arch/x86/events/core.c | 13 ++++++++-----
arch/x86/events/intel/core.c | 19 ++++++++-----------
arch/x86/events/perf_event.h | 2 +-
4 files changed, 20 insertions(+), 22 deletions(-)

diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c
index bd99d2a..8b70237 100644
--- a/arch/x86/events/amd/core.c
+++ b/arch/x86/events/amd/core.c
@@ -1224,16 +1224,14 @@ static ssize_t amd_event_sysfs_show(char *page, u64 config)
return x86_event_sysfs_show(page, config, event);
}

-static u64 amd_pmu_limit_period(struct perf_event *event, u64 left)
+static void amd_pmu_limit_period(struct perf_event *event, s64 *left)
{
/*
* Decrease period by the depth of the BRS feature to get the last N
* taken branches and approximate the desired period
*/
- if (has_branch_stack(event) && left > x86_pmu.lbr_nr)
- left -= x86_pmu.lbr_nr;
-
- return left;
+ if (has_branch_stack(event) && *left > x86_pmu.lbr_nr)
+ *left -= x86_pmu.lbr_nr;
}

static __initconst const struct x86_pmu amd_pmu = {
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index b074e71..1e90bc7 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -621,8 +621,9 @@ int x86_pmu_hw_config(struct perf_event *event)
event->hw.config |= event->attr.config & X86_RAW_EVENT_MASK;

if (event->attr.sample_period && x86_pmu.limit_period) {
- if (x86_pmu.limit_period(event, event->attr.sample_period) >
- event->attr.sample_period)
+ s64 left = event->attr.sample_period;
+ x86_pmu.limit_period(event, &left);
+ if (left > event->attr.sample_period)
return -EINVAL;
}

@@ -1396,9 +1397,9 @@ int x86_perf_event_set_period(struct perf_event *event)
left = x86_pmu.max_period;

if (x86_pmu.limit_period)
- left = x86_pmu.limit_period(event, left);
+ x86_pmu.limit_period(event, &left);

- per_cpu(pmc_prev_left[idx], smp_processor_id()) = left;
+ this_cpu_write(pmc_prev_left[idx], left);

/*
* The hw event starts counting from this event offset,
@@ -2677,7 +2678,9 @@ static int x86_pmu_check_period(struct perf_event *event, u64 value)
return -EINVAL;

if (value && x86_pmu.limit_period) {
- if (x86_pmu.limit_period(event, value) > value)
+ s64 left = value;
+ x86_pmu.limit_period(event, &left);
+ if (left > value)
return -EINVAL;
}

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index feed732..92cc390 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -4344,28 +4344,25 @@ static u8 adl_get_hybrid_cpu_type(void)
* Therefore the effective (average) period matches the requested period,
* despite coarser hardware granularity.
*/
-static u64 bdw_limit_period(struct perf_event *event, u64 left)
+static void bdw_limit_period(struct perf_event *event, s64 *left)
{
if ((event->hw.config & INTEL_ARCH_EVENT_MASK) ==
X86_CONFIG(.event=0xc0, .umask=0x01)) {
- if (left < 128)
- left = 128;
- left &= ~0x3fULL;
+ if (*left < 128)
+ *left = 128;
+ *left &= ~0x3fULL;
}
- return left;
}

-static u64 nhm_limit_period(struct perf_event *event, u64 left)
+static void nhm_limit_period(struct perf_event *event, s64 *left)
{
- return max(left, 32ULL);
+ *left = max(*left, 32LL);
}

-static u64 spr_limit_period(struct perf_event *event, u64 left)
+static void spr_limit_period(struct perf_event *event, s64 *left)
{
if (event->attr.precise_ip == 3)
- return max(left, 128ULL);
-
- return left;
+ *left = max(*left, 128LL);
}

PMU_FORMAT_ATTR(event, "config:0-7" );
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 7ae1a6c..e82d2d2 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -781,7 +781,7 @@ struct x86_pmu {
struct event_constraint *event_constraints;
struct x86_pmu_quirk *quirks;
int perfctr_second_write;
- u64 (*limit_period)(struct perf_event *event, u64 l);
+ void (*limit_period)(struct perf_event *event, s64 *l);

/* PMI handler bits */
unsigned int late_ack :1,
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